Page 41 - Principles of Catalyst Development
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STRUCTURE OF CATALYSTS 27
function:
high surface area
porosity
function: mechanical properties
chemical activity stability
types: dual functional
activity
metals modification of
semlcond uc tor active component
and sulfides
insulator oXides types:
and sulfides high m. p. oxides
cloys
carbon
PROMOTERS
function:
on support
structural
activity inhibition
activity promotion
on active component
electronic
morphology
poisoning
Figure 2.2. Catalyst components.
TABLE 2.1. Classification of Active Components
Conductivity I
Reaction
Class type Reactions Examples
Metals Conductors Hydrogenation Fe, Ni, Pt
Redox Hydrogenolysis Pd, Cu, Ag
Oxidation
Oxides and Semiconductors Selective NiO, ZnO, CuO
sulfides Redox hydrogenation
Hydrogenolysis Cr20], MoS 2
Oxidation
Oxides Insulators Polymerization AI 20" Si0 2 , MgO
Carbonium ions Isomerization SiOr Al 2O,
Cracking
Dehydration Zeolites